A particle beam processing device is commonly used to expose a substrate or coating to highly accelerated particle beams, such as an electron beam (EB), to cause a chemical reaction on the substrate or coating.
An electron is a negatively charged particle found in all matter. Electrons revolve around the nucleus of an atom much like planets revolve around the sun. By sharing electrons, two or more atoms bind together to form molecules. In EB processing, energetic electrons are used to modify the molecular structure of a wide variety of products and materials. For example, electrons can be used to alter specially designed liquid coatings, inks and adhesives. During EB processing, electrons break bonds and form charged particles and free radicals. These radicals then combine to form large molecules. By this process, the liquid is transformed into a solid. This process is known as polymerization.
Liquid coatings treated with EB processing may include printing inks, varnishes, silicone release coatings, primer coatings, pressure sensitive adhesives, barrier layers and laminating adhesives. EB processing may also be used to alter and enhance the physical characteristics of solid materials such as paper, substrates and non-woven textile substrates, all specially designed to react to EB treatment.
A particle beam processing device generally includes three zones, i.e., a vacuum chamber zone where a particle beam is generated, a particle accelerator zone, and a processing zone. In the vacuum chamber, a tungsten filament is heated to about 2400K, which is the thermionic emission temperature of tungsten, to create a cloud of electrons. A positive voltage differential is then applied to the vacuum chamber to extract and simultaneously accelerate these electrons. Thereafter, the electrons pass through a thin foil and enter the processing zone. The thin foil functions as a barrier between the vacuum chamber and the processing zone. Accelerated electrons exit the vacuum chamber through the thin foil and enter the processing zone at atmospheric conditions.
A window tile assembly can be used to support the foil in electron beam processing systems. Current window tile assembly features have a consistent cross-sectional geometry throughout the depth of the tile or window in the direction perpendicular to the foil.
Accordingly, there is a need for window tile assemblies that utilizes a non-uniform cross-sectional geometry throughout the depth of the tile, which can increase electron throughput and improve efficiency in electron beam processing systems.